Regeneration of detrusor muscle after subtotal cystectomy in the rat: Effects on contractile proteins and bladder mechanics

The aim of the present study was to determine to what extent adult rats can produce new contracting bladder muscle and to see if such newly formed bla dder tissue possesses characteristic mechanical properties or whether the a bility to recover mechanically is so pronounced that the prehistory of the bladder is unimportant. Subtotal cystectomy was performed in adult female r ats, leading to a pronounced decrease in total bladder weight. At 10 weeks, bladder weight had normalized. The histological appearance of such bladder s was similar to that of the controls. Active and passive length-tension re lations for the detrusor muscle were determined in controls and up to 10 we eks after surgery. Immediately after surgery active and passive forces show ed a leftward shift and maximum active force decreased markedly. With time the length-tension curves shifted back to normal, but a decreased active fo rce still remained at 10 weeks. Detrusor actin concentration and detrusor m yosin/actin ratio were unaffected by the subtotal cystectomy. Intermediate filament protein/actin ratio showed a significant but transitory increase. We conclude that there is a remarkable recovery of detrusor muscle function after subtotal cystectomy, leading to a normalization of optimum length fo r active force and a net synthesis of contractile and cytoskeletal proteins . The ability to produce active force does, however, not fully recover. Neu rourol. Urodynam,. 20:685-697, 2001. (C) 2001 Wiley-Liss, Inc.